My relatives who nest along the Aleutian Islands tell me that they live on the "ring of fire," an area surrounding the Pacific Ocean that is home to 75 percent of the world's volcanoes.
Alaska alone is home to 8 percent of the world's active volcanoes, and about 80 percent of all active volcanoes within the United States. More than 100 volcanoes and volcano fields have been active here within the past 1.5 million years, although only 40 have been active during recorded time. With so many volcanoes, you must be wondering how scientists keep track of them without visiting every single one.
You humans have sent up satellites into orbit that look back at Earth from much higher up than I could ever fly! From my perspective, I can usually see only one volcano at a time. The new Landsat satellites orbit the Earth at 705 kilometers (interactivity 3.1) and can look at a 183 kilometers wide area in one pass.
Objects that are hot emit a lot of energy, which a satellite's infrared sensors can detect and record. The hotter the object the brighter it appears on the image. Before a volcano erupts it usually has increased thermal activity which appears as elevated surface temperatures (hot spots) around the volcano's crater. Early detection of a hot spot and monitoring is a key factor in predicting possible volcanic eruptions. Take a look at this infrared satellite image. Can you find and click on the hottest spot? (interactivity 3.2)
A dormant volcano may look like a beautiful mountain. Do you want to see what it looks like when it erupts? (interactivity 3.3)
This is a 2001 satellite image of Mt. Cleveland erupting out in the Aleutian Islands. Look at all that ash! Did you know that ash is a serious hazard for the aviation industry? (more information 3.1). It can seriously damage planes and cause engines to temporarily fail, possibly leading to a disastrous crash.
Scientists carry out numerical modeling to predict the movement and spread of ash plumes. To see a sample animation for a plume from Mt. Cleveland, Click here (interactivity 3.4). This analysis was made using a program named "PUFF." The yellow stars represent airplanes. Once they have observed or been affected by the ash plume, they turn red. Based on predictions from models such as PUFF, scientists can warn the aviation industry. That's a good thing to do!
Oh it's hot! Let's move on to a cooler place!
More information 3.1:
(Picture showing the air traffic routes above the Aleutian islands, location of volcanoes and historic eruptions). The airspace above the Aleutian Islands is one of the heaviest traveled in the world, with more than 50,000 large aircraft per year and 10,000 passengers per day traveling between Asia and North America and Europe. (Source: Alaska Volcano Observatory)
On December 15, 1989, KLM Flight 867 from Amsterdam was descending into Anchorage International Airport when it flew though a thick cloud of ash from Mt. Redoubt. All four engines stalled and the standby electrical system failed. After descending more than 14,000 feet, the crew was finally able to restart the engines and safely land the plane. In this case the ash caused more than $80 million in damage to the plane, but fortunately no lives were lost. (Source: US Geological Survey)
Conversion calculator - kilometers to miles and reverse. One can enter any numeric digit and the calculator converts on the click of a button.
Hot spot detection. A gray scale AVHRR image of Mt. Cleveland and surrounding area is presented. The brightest (white) region on this image is the hot spot due to eruption of Cleveland Volcano. Clicking on the white hot spot, the Canada goose standing close by animates "Awesome". Clicking on any other part of the image the same bird shakes head in an animation with the message "Try again".
Volcanic Eruption: On clicking the 'click here' tab, the whole screen shakes, the picture on the left showing a peaceful volcano changes to a picture of an erupting volcano, and Tutangiaq, the Canada goose that was earlier looking at the volcano runs to the right away from the volcano.
Puff modeling results: Clicking on the "Click here" tab displays the results of a "PUFF" model simulation of the eruption of the Cleveland volcano. The plume from the volcano is shown to be splitting up and traveling a long distance reaching unto the western US states.